In this task, you're given a question, a context passage, and four options which are terms from the passage. After reading a passage, you will get a brief understanding of the terms. Your job is to determine by searching and reading further information of which term you can answer the question. Indicate your choice as 'a', 'b', 'c', or 'd'. If you think more than one option is plausible, choose the more probable option to help you answer the question.

Question: How many years after the release of the PC-8801 was the PC-9801 released? Passage:The initial versions of Xak: The Art of Visual Stage were released for NEC's PC-8801 and PC-9801 systems in June 1989. These were then followed by graphically distinct releases for the MSX2 (November 1989) and Sharp X68000 (April 1990). In 1992, the game was released for the PC Engine along with its sequel, , in the one-disc compilation Xak I & II. Ported by Riot, the game features animated cut scenes and requires the Super System Card update if played on the PC Engine's original CD-ROM add-on. Another console port was published by Sunsoft for the Super Famicom in February 1993. The latest visually enhanced remake was developed for Japanese mobile phones and became available on Vodafone live! on June 1, 2004. The game was the first release in Bandai's "RPG Empire" line of role-playing games.
 Links: a. Bandai b. X68000 c. Vodafone live! d. NEC
d